Southern Brazil, eastern Paraguay, and easternmost Argentina

This area, extending through southern Brazil, and western Argentina and Paraguay, represents the largest portions of the Brazilian Atlantic semi-deciduous forest region. This region serves as a corridors for species migration between moist and semi-deciduous forests and also between Atlantic forests and Cerrado habitats (Klein 1985; Mantovani 1993). Due to this, species richness is high, although endemism is relatively low. Only five percent of the original forest remains. There are a number of protected areas; however, timber extraction, agriculture and hunting threaten the remaining small patches of forest.

Scientific Code

(NT0150)

Ecoregion Category

Neotropical

Size

186,800 square miles

Status

Critical/Endangered

Habitats

Description Location and General DescriptionParana/Parnaíba interior forests represent a large block of Atlantic semi-deciduous forest spread from Southeast Brazil and Paraguay to northern Argentina. The climate is subtropical with annual precipitation around 1,200 to 1,600 mm (Salis et al. 1995). In the dry season, from April through September, frosts occur frequently. The ancient plateaus and slopes of the Brazilian Plateau occupies this portion of Brazil. Soils throughout the ecoregion range from the fertile to impoverished latosols and podzols. Forests are spread from river plains to middle-level plateaus at 800 m elevation.

The main vegetation type of this ecoregion is Atlantic semi-deciduous forest, with an emergent strata 35 m tall (Veloso et al. 1991). Canopy layers are populated largely by tree species of the families Lauraceae, Apocynaceae, Leguminosae and their respective genera Ocotea, Aspidosperma, and Machaerium (Rodrigues & Shepherd 1992). Some focal tree species include Cariniana estrellensis, Copaifera langsdorfii, Alchornea triplinervia, and Aspidosperma polyneuron. Gallery forests and flooded grasslands are also found bordering the ecoregions larger rivers (Gibbs & Leitão Filho 1978; Campos 1999). Richness of plant and animal species that characterizes semi-deciduous forests sets this ecoregion apart from other portions of the Brazilian Atlantic forest. About 40 percent of tree canopy species are deciduous or semi-deciduous (Morellato et al. 1989).

Biodiversity FeaturesParana/Paranaíba interior forests represent the largest portions of the Brazilian Atlantic semi-deciduous forest ecoregion. These forests are rich in species of Leguminosae, Myrtaceae, Lauraceae, and Rutaceae (Leitão Filho 1992). In the Brazilian State of São Paulo alone, at least 662 woody plant species have been described (Leitão Filho 1992). Plant species are distributed along elevational and latitudinal gradients (Klein 1985, Salis et al. 1995), producing singular plant species composition through out the ecoregion along the lines of elevation.

Paraná/Paranaíba interior forests are home to Atlantic rare vertebrates such as the golden-rumped lion tamarin (Leontophitecus chysopygus) and the brown howler monkey (Alouatta fusca) (Marinho-Filho 1992; Cullen Jr. & Padua 1999), which have a few populations scattered in the remaining remnants of these forests. Dozens of threatened plants such as Trichilia elegans and Persea punctata and mammals including Ocelot (Leopardus pardalis) are found (São Paulo 1998, 1999) in this coastal forest ecoregion. Some representative birds of the ecoregion include black-fronted piping-guan (Pipile jacutinga), helmeted woodcreeper (Dryocopus galeatus), and São Paulo tyrannulet (Phylloscartes paulistus). From an evolutionary point of view, Parana/Paranaíba interior forests have played a key role as corridors for species migration between moist and semi-deciduous forests and also between Atlantic forests and Cerrado habitats (Klein 1985; Mantovani 1993).

Parana/Paraiba interior forests represent the largests and best protected portions of the Brazilian Atlantic semideciduous forest. These forests are rich in species of Leguminosae, Myrtaceae, Lauraceae and Ruraceae (Leitão Filho 1992). Only in São Paulo Brazilian state, at least, 662 woody plant species are found (Leitão Filho 1992). Plant species are distributed along altitudinal and latitudinal gradients (Klein 1985, Salis et al. 1995), producing singular plant species composition.

Current StatusParana/Paranaíba forests have been reduced in area by 95 percent in Brazil (SOS MATA ATLÂNTICA 1998). Remaining vegetation is represented by approximately 17,211 km2 of semi-deciduous forests. The largest blocks of forest (300 to 1,000 km2 are protected public areas (Lima & Capobianco 1997), but thousands of 0.01 to 1 km2 remnants, surrounded by pastures and agriculture, represent the dominant biological scenery (Viana et al. 1997).

Types and Severity of ThreatsSuch remnants are expected to lose a significant part of their biodiversity due to the increase of lianas and ruderal species (Viana et al. 1997; Tabarelli et al. 1999). Protected areas occupy only 1,866.3 km2 of this semi-deciduous forest ecoregion (Silva & Dinnouti 1999). Timber extraction, agriculture and hunting represent continuous threats to the biodiversity of Paraná/Paraiba forests. Such activities will increase the pressure on timber trees, game species, and large carnivores (Cullen Jr. & Pádua 1999; Cullen Jr. et al. 1999).

Justification of Ecoregion DelineationMost Brazilian expertise (e.g., C. T. Rizzini, H. P. Veloso, ) recognize Parana/Paraíba interior forests as a distinct dry extension of the Atlantic coastal forest set along the depression of Paraná river and its tributaries. Broad scale delineation’s for these interior forests in southern Brazil were based on the vegetative classifications of the IBGE map (1993). Linework was derived by lumping current vegetative coverage’s of the IBGE map into their historic limits, including: "secondary semideciduous forests" and "secondary deciduous forest". The boundary for the extension between Bahia forests and Serra do Mar forests was drawn along the Rio Grande, Rio Preto, and Rio Paraiba to the north and along the "dense ombrophilous forest" delineation, to separate this from these floristically distinct forests. The linework was then refined at a priority setting workshop (WWF, in prep.), which also established the borders along the western boundary with the Humid Chaco. The historic extension of this ecoregion into Argentina was according to Morello (1968), Daniele and Natenzon (1994), and Cabrera (1976).